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Hayabusa 2 (Хаябуса-2), Procyon – H-IIA F26 – Танэгасима – 03.12.2014 04:22:04 UTC, (успешно)
Approach to the 2nd touchdown –Part 3: To go or not to go–

After the generation of the artificial crater on the surface of asteroid Ryugu using the Small Carry-on Impactor (SCI) on April 5, four operations were conducted to observe near the new crater. As was mentioned in Part 2, the third descent operation also successfully dropped a target marker at the touchdown candidate site. Finally, here we present “To go, or not to go, that is the question”.

Although the first touchdown was successful, going for a second touchdown is “the question” because touchdown is a high-risk operation. This is especially true in the case of Ryugu, which has no large, flat areas. The spacecraft therefore needs precise control to avoid a collision in rocky locations. In short, just because we have succeeded in the past does not mean we can easily do so again.

The spacecraft is operating far into space, in a harsh environment and with a communication time too long for us to correct problems if they occur. We always operate alongside the risk of failure or breakdown. Therefore, our project members will always feel uneasy about the prospect of performing a touchdown. But being vaguely anxious does not make any progress. The situation needs to be considered fr om a scientific and technical standpoint.

Two major issues need to be considered. The first is whether the second touchdown has significant scientific and engineering merit. If there is little extra to be gained, and as the first touchdown was already successful, there is no point in performing this twice. A second issue is the risk of the touchdown operations. If the risk is high, then the descent would be reckless.

First, let’s consider the scientific and engineering value of the second touchdown. Fr om the observations around the site of the artificial crater, it was clear that there is ejecta from the crater in the region wh ere the second touchdown is planned (Figure 1). In other words, if we go ahead with the touchdown, we will reliably be able to collect subsurface material from Ryugu. This is high scientific value. In addition, this would also result in samples being collected from multiple locations on the asteroid. This also adds to the scientific value as it gives more universal information about Ryugu, rather than the possibility you may have collected material from an unusual spot. From an engineering perspective, this will be the world’s first collection of samples from multiple locations and also the first sample from below the surface. This naturally means the value is high. Combined, this confirmed that the science and engineering value of a second touchdown is significant.

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Figure 1: Change in the surface reflectivity due to the artificial crater formed with the Small Carry-on Impactor (SCI). The black regions indicate areas that have darkened after the collision. The planned touchdown point is in the vicinity of C01-C in the figure; a region that has darkened after the generation of the artificial crater. That is, it is thought that subsurface material from the artificial crater has been deposited in this region. (※ Image credit: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST and Kobe University.)

Next to consider is the risk of the operation. If this is too high, there is an argument that this is not a chance that should be taken. We therefore first sel ected places that touchdown could be performed near the artificial crater, and proceeded to collect detailed information on the topography of these touchdown candidate points during the low altitude descent operations. We also were able to drop a target marker at one of these locations. This eventually became the planned touchdown site.

The planned touchdown site is about 20m away towards the north from the artificial crater generated with the SCI. This is an area with a radius of about 3.5m, which was named C01-Cb by the project. There are dangerous boulders around the area and also substantial rock piles in C01-Cb. After estimating the height of these rocks, creating a three-dimensional map and confirming the danger during a touchdown operation, it was judged that there would not be a problem if the spacecraft were to touchdown in this region.

A further technical issue was that the amount of light received by the optical systems on Hayabusa2 (the Optical Navigation Camera – Wide angle, ONC-W1, and laser range finder, LRF) decreased during the first touchdown. This is thought to be due to dust that soared upwards at the time of touchdown and adhered to the instruments. To cope with this problem, we decided to compensate for the decrease in the amount of received light by lowering the altitude at which to switch to the affected optical system. We confirmed that this approach works well during the low altitude operations.

As a result of the above examination, it was confirmed that the risk during the second touchdown is equal or less than the risk of the first touchdown. Since the second touchdown is of high scientific and engineering value, we decided the project should perform a second touchdown to collect a sample fr om asteroid Ryugu. This was approved by ISAS on June 21 and by JAXA as a whole on June 25, whereupon is was decided to do a second touchdown.

The second touchdown will be attempted on July 11. We will proceed with our mission with care, but boldly go.

※Please use the displayed credit when reproducing these images. In the case wh ere an abbreviated form is necessary, please write "JAXA, University of Tokyo & collaborators".

Hayabusa2 Project
Ещё один адрес трансляции посадки на ТыТрубе (jaxasgm)

HAYABUSA2@JAXA‏ @haya2e_jaxa 10 ч. назад

This Thursday (July 11), Hayabusa2 will touchdown on asteroid Ryugu to collect a 2nd sample. You can tune in to our webcast from 09:30 JST (01:30 BST / Wed. 20:30 EDT / 17:30 PDT) here: https://www.youtube.com/watch?v=hnJX9obXzPU&feature=youtu.be …

And press briefing from 14:00 JST:
00:30 UTC (03:30 ДМВ) 11.07.2019
10 ИЮЛ, 05:36
Японский зонд "Хаябуса-2" начал снижаться перед второй посадкой на астероид Рюгу

Примерно через 22 часа после начала снижения зонд окажется в 500 метрах от астероида и его переведут в автоматический режим управления

ТОКИО, 10 июля. /ТАСС/. Японский зонд "Хаябуса-2" ("Сокол-2"), находящийся вблизи отдаленного астероида Рюгу, в среду начал снижаться с орбиты на высоте 20 км, чтобы через сутки совершить вторую посадку на это космическое тело. Об этом сообщило Японское агентство аэрокосмических исследований (JAXA).

На первом этапе аппарат будет опускаться со скоростью 40 см в секунду, пока не приблизится к Рюгу на расстояние 5 км. После этого скорость уменьшится до 5 см в секунду. Контролировать проведение операции и корректировать траекторию движения японские специалисты смогут благодаря установленной на "Хаябусе-2" камере, однако сигнал от нее доходит до Земли только спустя 10 минут.

Примерно через 22 часа после начала снижения зонд окажется в 500 метрах от астероида. Затем из-за отсутствия возможности оперативно следить за поведением аппарата с Земли его переведут в автоматический режим управления. В качестве ориентира для посадки "Хаябусы-2" будет использовать сброшенную ранее на поверхность космического тела контрольную метку.

Само приземление должно продлиться всего несколько секунд. За это время зонд должен выстрелить в поверхность астероида металлической пулей, которая поднимет вверх пыль и фрагменты грунта. Их в свою очередь соберет установленный на аппарате специальный пылесос. После этого "Хаябуса-2" вернется в свое обычное положение на расстоянии 20 км от Рюгу.
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Японский космический зонд "Хаябуса-2" начал снижение к астероиду Рюгу

ТОКИО, 10 июл – РИА Новости, Ксения Нака. Японский космический зонд "Хаябуса-2" начал снижение к астероиду Рюгу, сообщило Японское аэрокосмическое агентство (JAXA).
"В 11.01 (05.01 мск) мы смогли убедиться в том, что космический зонд начал снижение из своей исходной точки, которая находится на высоте 20 километров. Как и планировалось, он начал снижение в 10.46 (04.46 мск). Скорость снижения составляет 40 сантиметров в секунду", - говорится в сообщении, размещенном на официальной странице JAXA в сети Twitter.
Зонд начал снижение с высоты в 20 километров от поверхности астероида. Как ожидается, двигаясь с крайне низкой скоростью от 40 до 10 сантиметров в секунду, что позволит с ювелирной точностью регулировать процесс снижения, зонд сможет приземлиться на заранее намеченную для этого площадку. Она находится в 20 метрах от центра искусственного кратера, который зонд создал на поверхности Рюгу в апреле этого года. Он стал первым в мире рукотворным кратером на поверхности космического тела. Теперь зонд должен собрать образцы породы, которую выбросило на поверхность при образовании кратера.

Ученые считают, что именно образцы породы, полученной из недр астероида, в большей степени сохраняющей свойства материи времен возникновения Солнечной системы, позволят человечеству приблизиться к разгадке образования Солнечной системы и появлению жизни.

Радиус участка, на который должен приземлиться "Хаябуса-2", всего около 7 метров, но именно здесь, по расчетам ученых, нет больших валунов, которые могли бы повредить зонд. Для того, чтобы скорректировать посадку, зонд выбросит маркер в двух метрах от площадки, который будет подавать световой сигнал и таким образом служить ориентиром для приземления.

Как ожидается, утром в четверг зонд сможет приземлиться на поверхность астероида.
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The 2nd touchdown

The 2nd touchdown operation will take place fr om July 9 – 11. Here, we describe the operation events and schedule (the operation is referred to as the “2nd touchdown” but denoted PPTD).

For discussion about the 2nd touchdown operation, please take a look at these recent articles on our website.
(1) Approach to the 2nd touchdown –Part 1: observations near the touchdown point−
(2) Approach to the 2nd touchdown –Part 2: details of the touchdown point−
(3) Approach to the 2nd touchdown –Part 3: to go, or not to go−

The first shift for the 2nd touchdown starts on July 9, where the set-up for the descent will be completed. The actual descent will begin on July 10 at 10:46 JST (on-board time). Initially, the descent will begin at a velocity of 40cm/s, matching that in previous operations. At 21:06 JST, the altitude will reach about 5km, whereupon the descent will slow to about 10 cm/s. On July 11 at 09:40 JST, the altitude will have reduced to 30m and the spacecraft will start to hover. Touchdown will be at about 10:05 JST at the earliest, and about 10:45 JST at the latest. Immediately after touchdown, the spacecraft will rise at a speed of about 65 cm/s and return to the home position on July 12. The entire touchdown operation is shown in Figure 1.

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Figure 1: Outline of the 2nd touchdown operation. The switch to using the Laser Range Finder (LRF) will take place during the descent fr om 30m. The time of touchdown indicated with the * is estimated to be around 10:05 JST (onboard time) at the earliest and about 10:45 JST at the latest (image credit: JAXA).
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The 2nd touchdown is the last big operation at Ryugu for the Hayabusa2 project. We will proceed with caution and the upmost care. Please wish us success…!

Hayabusa2 Project

※ Please use the displayed credit when reproducing these images..
※1 If an abbreviated form is needed, please write "JAXA, University of Tokyo & collaborators".
Опубликованы материалы пресс-конференции 09.07.2019

Hayabusa2_Press20190709_ver8_en3.pdf - 2.2 MB, 25 стр, 2019-07-10 07:29:08 UTC

HAYABUSA2@JAXA‏ @haya2e_jaxa 15 ч. назад

[PPTD] July 10 at 11:01 JST. We have confirmed the spacecraft has started its descent from the home position (altitude of about 20km). The spacecraft begun its descent at 10:46 JST (onboard time) as scheduled. The descent speed is about 40cm/s.

12 ч. назад

[PPTD] July 10 at 14:04 JST. The spacecraft altitude is now about 15km. We are continuing to descend smoothly.

9 ч. назад

[PPTD] July 10 at 16:55 JST. The spacecraft altitude is now about 11km.

8 ч. назад

[PPTD] July 10 at 17:39 JST. The spacecraft altitude is now about 10km. Currently, there are about 20 members in the control room and the work is quiet. By the way, the one-way propagation time for a radio-wave to reach the spacecraft is about 815 seconds (13mins 35s) today.

6 ч. назад

[PPTD] July 10 at 20:28 JST. The altitude of the spacecraft is approximately 6km.

5 ч. назад

[PPTD] July 10 at 21:36 JST. Gate 2 check. It was confirmed that the spacecraft decelerated as planned (onboard 21:06 JST) and is descending at about 10 cm/s. Spacecraft and ground system were also confirmed to be normal and continuation of the operation is GO.
HAYABUSA2@JAXA‏ @haya2e_jaxa 3 ч. назад

These amazing stereoscopic images are by @DrBrianMay & Claudia Manzoni. They show a particularly clear view of the large rock formation, Otohime Saxum. The top two images are with parallel stereoscopy and the bottom two use cross-eyed stereoscopy. Details: http://www.hayabusa2.jaxa.jp/en/topics/20190710e_Stereo_DrMay/ …

HAYABUSA2@JAXA‏ @haya2e_jaxa 3 ч. назад

[PPTD] July 10 at 23:23 JST. The altitude of the spacecraft is now about 4km. This photo is a navigation image received at 23:05 JST.

HAYABUSA2@JAXA‏ @haya2e_jaxa 19 мин. назад

[PPTD] Hayabusa2 Live broadcast:
Time: Thursday. July 11 09:30 - 12:00 JST (Showing past operation clips from 09:00)

・Japanese (with live subtitles): https://fanfun.jaxa.jp/jaxatv/detail/14884.html …

・English (with simultaneous translation):
https://www.youtube.com/watch?v=hnJX9obXzPU ...
00:30 - 03:00 UTC 11.07.2019
Изменено: tnt22 - 11.07.2019 01:46:03
HAYABUSA2@JAXA‏ @haya2e_jaxa 21 мин. назад

[PPTD] Press conference live relay:
Time: Thursday, July 11 14:00~ JST

・Japanese: https://fanfun.jaxa.jp/jaxatv/detail/14882.html …

・English (with simultaneous translation):
https://www.youtube.com/watch?v=VfuT9CVbIG8 ...
~05:00 UTC 11.07.2019
HAYABUSA2@JAXA‏ @haya2e_jaxa 20 мин. назад

[PPTD] July 11 at 07:15 JST. The spacecraft altitude is now about 1km.
HAYABUSA2@JAXA‏ @haya2e_jaxa 21 мин. назад

[PPTD] July 11 at 08:56 JST. The altitude of the spacecraft has reached about 350m.
HAYABUSA2@JAXA‏ @haya2e_jaxa 9 мин. назад

[PPTD] July 11th at 09:18 JST. The altitude of the spacecraft has reached about 250m.
HAYABUSA2@JAXA‏ @haya2e_jaxa 5 мин. назад

[PPTD] July 11 at 09:26 JST. The spacecraft has reached an altitude of 200m.
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